Preparation method for metal-modified SAPO molecular sieve

Abstract

A preparation method for a metal-modified SAPO molecular sieve is disclosed, characterized in adding a raw powder of the SAPO molecular sieve to a solution containing metal ions for performing ion exchange, and then washing and drying the obtained solid after ion exchange, so as to obtain the metal-modified SAPO molecular sieve. The metal-modified SAPO molecular sieve prepared has a relatively high degree of crystallinity, and the metal elements occupy the ionic positions in the channels and/or cages of the SAPO molecular sieve, and the metal-modified SAPO molecular sieve shows excellent catalytic performance in the catalytic reaction.

The invention claimed is: 
     
       1. A preparation method for a metal-modified SAPO molecular sieve, which comprises at least the following steps:
 adding SAPO molecular sieve raw powder to a solution containing metal ions and performing ion exchange, and then 
 washing and drying the obtained solid after the ion exchange, so as to obtain the metal-modified SAPO molecular sieve 
 
       wherein the molecular sieve raw powder has not been calcined at a temperature above 300° C., and an organic templating agent and water are contained in channels and cages of the molecular sieve raw powder; 
       wherein the metal ion is at least one selected from Group IA metal ions, Group IIA metal ions, Group IIIA metal ions, Group VA metal ions, Group IVB metal ions, Group VB metal ions, Group VIIB metal ions, Group VIII metal ions, Group IB metal ions, lanthanide metal ions, and wherein there are no steps of calcining the molecular sieve raw powder and ammonium exchange in the method; wherein metal ions are located at ion sites in channels and/or cages of the metal-modified SAPO molecular sieve; the mass ratio of the SAPO molecular sieve raw powder to the solution containing metal ions is in a range from 1:8 to 1:100, the metal ion concentration in the solution containing metal ions is in a range from 0.005 mol/L to 0.5 mol/L; the ion exchange temperature is in a range from 40° C. to 90° C., and the ion exchange time is in a range from 0.5 h to 10 h. 
     
     
       2. The method according to  claim 1 , wherein the SAPO molecular sieve raw powder is at least one selected from SAPO-34 molecular sieve raw powder, SAPO-35 molecular sieve raw powder, SAPO-56 molecular sieve raw powder, SAPO-18 molecular sieve raw powder, SAPO-5 molecular sieve raw powder, SAPO-11 molecular sieve raw powder, DNL-6 molecular sieve raw powder. 
     
     
       3. The method according to  claim 1 , wherein the metal ion is at least one selected from copper ions, iron ions, lanthanum ions, cerium ions, cobalt ions, nickel ions, manganese ions, magnesium ions, vanadium ions, zirconium ions, barium ions, platinum ions, gold ions, palladium ions, silver ions, rhodium ions, ruthenium ions, aluminum ions, bismuth ions, gallium ions, calcium ions, strontium ions, lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions. 
     
     
       4. The method according to  claim 1 , wherein an organic templating agent is used in the synthesis of the SAPO molecular sieve raw powder. 
     
     
       5. The method according to  claim 4 , wherein the organic templating agent used in the synthesis of the SAPO-34 molecular sieve raw powder contains at least one organic amine compound with no more than 8 carbon atoms; the organic templating agent used in the synthesis of SAPO-18 molecular sieve raw powder contains at least one organic amine compound with no more than 8 carbon atoms; the organic templating agent used in the synthesis of SAPO-56 molecular sieve raw powder contains at least one organic amine compound with no more than 10 carbon atoms; the organic templating agent used in the synthesis of SAPO-5 molecular sieve raw powder contains at least one organic amine compound with no more than 9 carbon atoms; the organic templating agent used in the synthesis of SAPO-11 molecular sieve raw powder contains at least one organic amine compound with no more than 8 carbon atoms; the organic templating agent used in the synthesis of SAPO-35 molecular sieve raw powder contains at least one organic amine compound with no more than 8 carbon atoms; and the organic templating agent used in the synthesis of DNL-6 molecular sieve raw powder contains at least one organic amine compound having no more than 8 carbon atoms. 
     
     
       6. The method according to  claim 1 , wherein the obtained solid is washed, dried and calcined at a temperature no less than 600° C., to obtain the metal-modified SAPO molecular sieve.